1. Field of the Invention
The present invention relates to a speed measure system of a vehicle that detects rotations of a drive gear that is rotated by a movement of a vehicle and of a driven gear that is gear-meshed with the drive gear and has a speed sensor that transfers the detected rotation to pulse signal.
2. Description of Related Art
Generally, a speed of a vehicle is transferred to a driver through a speedometer or a tacho graph of an instrument panel.
Since this art has been developed to be suited to a vehicle speed signal of 5096 pulse per Kilometer, a driven gear and a gear ratio of a joint or a transmission itself are adjusted to set a vehicle speed ratio according to specifications of a rear axle or a tire of a vehicle.
However, specifications are increased in geometrical progression according to a rear axle ratio and a tire radius of a kind of a vehicle. Further, the number of the gear is used to adjust the gear ratio, and therefore it is hard to achieve an accurate speed ratio thereof.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.